An X-ray diffraction device is known as a device which analyzes a crystalline structure of a specimen using X-rays. The X-ray diffraction device is constructed of an X-ray generating means disposed at a position from which it can irradiate the surface of a specimen at an angle θ and an X-ray detecting means such as a counter disposed at a position of angle 2θ formed by the irradiation direction and measuring point of the specimen, and irradiates the specimen with X-rays having a known single wavelength λ by sequentially rotating and moving the X-ray generating means and X-ray detecting means and measures intensity of X-rays at the angle θ, that is, diffraction intensity.
Since diffracted X-rays are diffracted at the angle θ which satisfies:2d sin θ=λ  [Formula 1]according to Bragg's law, it is possible to know a crystal face spacing d and diffraction intensity of the specimen from the diffraction graphic and obtain data for determining an atomic arrangement of the specimen.
However, the X-ray diffraction device requires a precise mechanism for sequentially rotating and moving the specimen and X-ray detecting means, that is, a goniometer, which not only complicates the device and increases the size of the device but also requires a rotation/movement operation time and measuring time at each position of movement, producing a problem that it takes quite a long time to obtain a measurement result.
To solve such a problem, an energy dispersion diffraction method as described in Non-Patent Document 1 is proposed.
According to this method, an X-ray generation device is disposed at a position of an angle θ with respect to the surface of a specimen, a means for detecting energy and intensity of X-rays simultaneously is disposed at a position of an angle 2θ formed by the irradiation direction and measuring point of the specimen, white X-rays are irradiated with θ and 2θ fixed and intensity of X-rays having energy E is measured.
Bragg's law is expressed centered on energy E as:E=hν=hc/λ=hc/2d sin θ  [Formula 2]Therefore, it is possible to determine an atomic surface spacing d and diffraction intensity by only measuring the relationship between the detected energy E and intensity of diffracted X-rays by keeping the angles of the X-ray generating means, specimen and X-ray detecting means to fixed positions and using a multichannel analyzer or the like.
Furthermore, since the X-rays which reach the detecting means also include fluorescent X-rays from the specimen, if these X-rays can be distinguished from diffracted X-rays, it is also possible to determine the kind of atoms of the specimen from fluorescent X-rays.
The energy at which diffracted rays emerge follows Bragg's law and also depends on the angle θ, and therefore there is also a proposal to conduct measurement at an appropriate angle at which diffracted rays and fluorescent X-rays do not overlap each other so as to distinguish diffracted rays from fluorescent X-rays.
Non-Patent Document 1: B. D. Cullity. Elements of X-Ray Diffraction, 2nd ed (Reading, Mass.: Addison-Wesley, 1977.)